net/sctp/endpointola.c

   1 /* SCTP kernel reference Implementation
   2  * Copyright (c) 1999-2000 Cisco, Inc.
   3  * Copyright (c) 1999-2001 Motorola, Inc.
   4  * Copyright (c) 2001-2002 International Business Machines, Corp.
   5  * Copyright (c) 2001 Intel Corp.
   6  * Copyright (c) 2001 Nokia, Inc.
   7  * Copyright (c) 2001 La Monte H.P. Yarroll
   8  *
   9  * This file is part of the SCTP kernel reference Implementation
  10  *
  11  * This abstraction represents an SCTP endpoint.
  12  *
  13  * This file is part of the implementation of the add-IP extension,
  14  * based on <draft-ietf-tsvwg-addip-sctp-02.txt> June 29, 2001,
  15  * for the SCTP kernel reference Implementation.
  16  *
  17  * The SCTP reference implementation is free software;
  18  * you can redistribute it and/or modify it under the terms of
  19  * the GNU General Public License as published by
  20  * the Free Software Foundation; either version 2, or (at your option)
  21  * any later version.
  22  *
  23  * The SCTP reference implementation is distributed in the hope that it
  24  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  25  *                 ************************
  26  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  27  * See the GNU General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * along with GNU CC; see the file COPYING.  If not, write to
  31  * the Free Software Foundation, 59 Temple Place - Suite 330,
  32  * Boston, MA 02111-1307, USA.
  33  *
  34  * Please send any bug reports or fixes you make to the
  35  * email address(es):
  36  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  37  *
  38  * Or submit a bug report through the following website:
  39  *    http://www.sf.net/projects/lksctp
  40  *
  41  * Written or modified by:
  42  *    La Monte H.P. Yarroll <piggy@acm.org>
  43  *    Karl Knutson <karl@athena.chicago.il.us>
  44  *    Jon Grimm <jgrimm@austin.ibm.com>
  45  *    Daisy Chang <daisyc@us.ibm.com>
  46  *    Dajiang Zhang <dajiang.zhang@nokia.com>
  47  *
  48  * Any bugs reported given to us we will try to fix... any fixes shared will
  49  * be incorporated into the next SCTP release.
  50  */
  51
  52 #include <linux/types.h>
  53 #include <linux/slab.h>
  54 #include <linux/in.h>
  55 #include <linux/random.h>       /* get_random_bytes() */
  56 #include <linux/crypto.h>
  57 #include <net/sock.h>
  58 #include <net/ipv6.h>
  59 #include <net/sctp/sctp.h>
  60 #include <net/sctp/sm.h>
  61
  62 /* Forward declarations for internal helpers. */
  63 static void sctp_endpoint_bh_rcv(struct work_struct *work);
  64
  65 /*
  66  * Initialize the base fields of the endpoint structure.
  67  */
  68 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
  69                                                 struct sock *sk,
  70                                                 gfp_t gfp)
  71 {
  72         struct sctp_hmac_algo_param *auth_hmacs = NULL;
  73         struct sctp_chunks_param *auth_chunks = NULL;
  74         struct sctp_shared_key *null_key;
  75         int err;
  76
  77         memset(ep, 0, sizeof(struct sctp_endpoint));
  78
  79         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
  80         if (!ep->digest)
  81                 return NULL;
  82
  83         if (sctp_auth_enable) {
  84                 /* Allocate space for HMACS and CHUNKS authentication
  85                  * variables.  There are arrays that we encode directly
  86                  * into parameters to make the rest of the operations easier.
  87                  */
  88                 auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
  89                                 sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
  90                 if (!auth_hmacs)
  91                         goto nomem;
  92
  93                 auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
  94                                         SCTP_NUM_CHUNK_TYPES, gfp);
  95                 if (!auth_chunks)
  96                         goto nomem;
  97
  98                 /* Initialize the HMACS parameter.
  99                  * SCTP-AUTH: Section 3.3
 100                  *    Every endpoint supporting SCTP chunk authentication MUST
 101                  *    support the HMAC based on the SHA-1 algorithm.
 102                  */
 103                 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
 104                 auth_hmacs->param_hdr.length =
 105                                         htons(sizeof(sctp_paramhdr_t) + 2);
 106                 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
 107
 108                 /* Initialize the CHUNKS parameter */
 109                 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
 110
 111                 /* If the Add-IP functionality is enabled, we must
 112                  * authenticate, ASCONF and ASCONF-ACK chunks
 113                  */
 114                 if (sctp_addip_enable) {
 115                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
 116                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
 117                         auth_chunks->param_hdr.length =
 118                                         htons(sizeof(sctp_paramhdr_t) + 2);
 119                 }
 120         }
 121
 122         /* Initialize the base structure. */
 123         /* What type of endpoint are we?  */
 124         ep->base.type = SCTP_EP_TYPE_SOCKET;
 125
 126         /* Initialize the basic object fields. */
 127         atomic_set(&ep->base.refcnt, 1);
 128         ep->base.dead = 0;
 129         ep->base.malloced = 1;
 130
 131         /* Create an input queue.  */
 132         sctp_inq_init(&ep->base.inqueue);
 133
 134         /* Set its top-half handler */
 135         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
 136
 137         /* Initialize the bind addr area */
 138         sctp_bind_addr_init(&ep->base.bind_addr, 0);
 139
 140         /* Remember who we are attached to.  */
 141         ep->base.sk = sk;
 142         sock_hold(ep->base.sk);
 143
 144         /* Create the lists of associations.  */
 145         INIT_LIST_HEAD(&ep->asocs);
 146
 147         /* Use SCTP specific send buffer space queues.  */
 148         ep->sndbuf_policy = sctp_sndbuf_policy;
 149
 150         sk->sk_write_space = sctp_write_space;
 151         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 152
 153         /* Get the receive buffer policy for this endpoint */
 154         ep->rcvbuf_policy = sctp_rcvbuf_policy;
 155
 156         /* Initialize the secret key used with cookie. */
 157         get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
 158         ep->last_key = ep->current_key = 0;
 159         ep->key_changed_at = jiffies;
 160
 161         /* SCTP-AUTH extensions*/
 162         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
 163         null_key = sctp_auth_shkey_create(0, GFP_KERNEL);
 164         if (!null_key)
 165                 goto nomem;
 166
 167         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
 168
 169         /* Allocate and initialize transorms arrays for suported HMACs. */
 170         err = sctp_auth_init_hmacs(ep, gfp);
 171         if (err)
 172                 goto nomem_hmacs;
 173
 174         /* Add the null key to the endpoint shared keys list and
 175          * set the hmcas and chunks pointers.
 176          */
 177         ep->auth_hmacs_list = auth_hmacs;
 178         ep->auth_chunk_list = auth_chunks;
 179
 180         return ep;
 181
 182 nomem_hmacs:
 183         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 184 nomem:
 185         /* Free all allocations */
 186         kfree(auth_hmacs);
 187         kfree(auth_chunks);
 188         kfree(ep->digest);
 189         return NULL;
 190
 191 }
 192
 193 /* Create a sctp_endpoint with all that boring stuff initialized.
 194  * Returns NULL if there isn't enough memory.
 195  */
 196 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 197 {
 198         struct sctp_endpoint *ep;
 199
 200         /* Build a local endpoint. */
 201         ep = t_new(struct sctp_endpoint, gfp);
 202         if (!ep)
 203                 goto fail;
 204         if (!sctp_endpoint_init(ep, sk, gfp))
 205                 goto fail_init;
 206         ep->base.malloced = 1;
 207         SCTP_DBG_OBJCNT_INC(ep);
 208         return ep;
 209
 210 fail_init:
 211         kfree(ep);
 212 fail:
 213         return NULL;
 214 }
 215
 216 /* Add an association to an endpoint.  */
 217 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 218                             struct sctp_association *asoc)
 219 {
 220         struct sock *sk = ep->base.sk;
 221
 222         /* If this is a temporary association, don't bother
 223          * since we'll be removing it shortly and don't
 224          * want anyone to find it anyway.
 225          */
 226         if (asoc->temp)
 227                 return;
 228
 229         /* Now just add it to our list of asocs */
 230         list_add_tail(&asoc->asocs, &ep->asocs);
 231
 232         /* Increment the backlog value for a TCP-style listening socket. */
 233         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 234                 sk->sk_ack_backlog++;
 235 }
 236
 237 /* Free the endpoint structure.  Delay cleanup until
 238  * all users have released their reference count on this structure.
 239  */
 240 void sctp_endpoint_free(struct sctp_endpoint *ep)
 241 {
 242         ep->base.dead = 1;
 243
 244         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 245
 246         /* Unlink this endpoint, so we can't find it again! */
 247         sctp_unhash_endpoint(ep);
 248
 249         sctp_endpoint_put(ep);
 250 }
 251
 252 /* Final destructor for endpoint.  */
 253 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 254 {
 255         SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 256
 257         /* Free up the HMAC transform. */
 258         crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 259
 260         /* Free the digest buffer */
 261         kfree(ep->digest);
 262
 263         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 264          * chunks and hmacs arrays that were allocated
 265          */
 266         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 267         kfree(ep->auth_hmacs_list);
 268         kfree(ep->auth_chunk_list);
 269
 270         /* AUTH - Free any allocated HMAC transform containers */
 271         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 272
 273         /* Cleanup. */
 274         sctp_inq_free(&ep->base.inqueue);
 275         sctp_bind_addr_free(&ep->base.bind_addr);
 276
 277         /* Remove and free the port */
 278         if (sctp_sk(ep->base.sk)->bind_hash)
 279                 sctp_put_port(ep->base.sk);
 280
 281         /* Give up our hold on the sock. */
 282         if (ep->base.sk)
 283                 sock_put(ep->base.sk);
 284
 285         /* Finally, free up our memory. */
 286         if (ep->base.malloced) {
 287                 kfree(ep);
 288                 SCTP_DBG_OBJCNT_DEC(ep);
 289         }
 290 }
 291
 292 /* Hold a reference to an endpoint. */
 293 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 294 {
 295         atomic_inc(&ep->base.refcnt);
 296 }
 297
 298 /* Release a reference to an endpoint and clean up if there are
 299  * no more references.
 300  */
 301 void sctp_endpoint_put(struct sctp_endpoint *ep)
 302 {
 303         if (atomic_dec_and_test(&ep->base.refcnt))
 304                 sctp_endpoint_destroy(ep);
 305 }
 306
 307 /* Is this the endpoint we are looking for?  */
 308 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 309                                                const union sctp_addr *laddr)
 310 {
 311         struct sctp_endpoint *retval = NULL;
 312
 313         if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
 314                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 315                                          sctp_sk(ep->base.sk)))
 316                         retval = ep;
 317         }
 318
 319         return retval;
 320 }
 321
 322 /* Find the association that goes with this chunk.
 323  * We do a linear search of the associations for this endpoint.
 324  * We return the matching transport address too.
 325  */
 326 static struct sctp_association *__sctp_endpoint_lookup_assoc(
 327         const struct sctp_endpoint *ep,
 328         const union sctp_addr *paddr,
 329         struct sctp_transport **transport)
 330 {
 331         struct sctp_association *asoc = NULL;
 332         struct sctp_transport *t = NULL;
 333         struct sctp_hashbucket *head;
 334         struct sctp_ep_common *epb;
 335         struct hlist_node *node;
 336         int hash;
 337         int rport;
 338
 339         *transport = NULL;
 340         rport = ntohs(paddr->v4.sin_port);
 341
 342         hash = sctp_assoc_hashfn(ep->base.bind_addr.port, rport);
 343         head = &sctp_assoc_hashtable[hash];
 344         read_lock(&head->lock);
 345         sctp_for_each_hentry(epb, node, &head->chain) {
 346                 asoc = sctp_assoc(epb);
 347                 if (asoc->ep != ep || rport != asoc->peer.port)
 348                         goto next;
 349
 350                 t = sctp_assoc_lookup_paddr(asoc, paddr);
 351                 if (t) {
 352                         *transport = t;
 353                         break;
 354                 }
 355 next:
 356                 asoc = NULL;
 357         }
 358         read_unlock(&head->lock);
 359         return asoc;
 360 }
 361
 362 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 363 struct sctp_association *sctp_endpoint_lookup_assoc(
 364         const struct sctp_endpoint *ep,
 365         const union sctp_addr *paddr,
 366         struct sctp_transport **transport)
 367 {
 368         struct sctp_association *asoc;
 369
 370         sctp_local_bh_disable();
 371         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 372         sctp_local_bh_enable();
 373
 374         return asoc;
 375 }
 376
 377 /* Look for any peeled off association from the endpoint that matches the
 378  * given peer address.
 379  */
 380 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 381                                 const union sctp_addr *paddr)
 382 {
 383         struct sctp_sockaddr_entry *addr;
 384         struct sctp_bind_addr *bp;
 385
 386         bp = &ep->base.bind_addr;
 387         /* This function is called with the socket lock held,
 388          * so the address_list can not change.
 389          */
 390         list_for_each_entry(addr, &bp->address_list, list) {
 391                 if (sctp_has_association(&addr->a, paddr))
 392                         return 1;
 393         }
 394
 395         return 0;
 396 }
 397
 398 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 399  * This may be called on BH or task time.
 400  */
 401 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 402 {
 403         struct sctp_endpoint *ep =
 404                 container_of(work, struct sctp_endpoint,
 405                              base.inqueue.immediate);
 406         struct sctp_association *asoc;
 407         struct sock *sk;
 408         struct sctp_transport *transport;
 409         struct sctp_chunk *chunk;
 410         struct sctp_inq *inqueue;
 411         sctp_subtype_t subtype;
 412         sctp_state_t state;
 413         int error = 0;
 414         int first_time = 1;     /* is this the first time through the looop */
 415
 416         if (ep->base.dead)
 417                 return;
 418
 419         asoc = NULL;
 420         inqueue = &ep->base.inqueue;
 421         sk = ep->base.sk;
 422
 423         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 424                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 425
 426                 /* If the first chunk in the packet is AUTH, do special
 427                  * processing specified in Section 6.3 of SCTP-AUTH spec
 428                  */
 429                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 430                         struct sctp_chunkhdr *next_hdr;
 431
 432                         next_hdr = sctp_inq_peek(inqueue);
 433                         if (!next_hdr)
 434                                 goto normal;
 435
 436                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 437                          * chunk while saving a pointer to it so we can do
 438                          * Authentication later (during cookie-echo
 439                          * processing).
 440                          */
 441                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 442                                 chunk->auth_chunk = skb_clone(chunk->skb,
 443                                                                 GFP_ATOMIC);
 444                                 chunk->auth = 1;
 445                                 continue;
 446                         }
 447                 }
 448 normal:
 449                 /* We might have grown an association since last we
 450                  * looked, so try again.
 451                  *
 452                  * This happens when we've just processed our
 453                  * COOKIE-ECHO chunk.
 454                  */
 455                 if (NULL == chunk->asoc) {
 456                         asoc = sctp_endpoint_lookup_assoc(ep,
 457                                                           sctp_source(chunk),
 458                                                           &transport);
 459                         chunk->asoc = asoc;
 460                         chunk->transport = transport;
 461                 }
 462
 463                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 464                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 465                         continue;
 466
 467                 /* Remember where the last DATA chunk came from so we
 468                  * know where to send the SACK.
 469                  */
 470                 if (asoc && sctp_chunk_is_data(chunk))
 471                         asoc->peer.last_data_from = chunk->transport;
 472                 else
 473                         SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
 474
 475                 if (chunk->transport)
 476                         chunk->transport->last_time_heard = jiffies;
 477
 478                 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
 479                                    ep, asoc, chunk, GFP_ATOMIC);
 480
 481                 if (error && chunk)
 482                         chunk->pdiscard = 1;
 483
 484                 /* Check to see if the endpoint is freed in response to
 485                  * the incoming chunk. If so, get out of the while loop.
 486                  */
 487                 if (!sctp_sk(sk)->ep)
 488                         break;
 489
 490                 if (first_time)
 491                         first_time = 0;
 492         }
 493 }